You have a much easier story.
I'm 47. Because of the network effect, using Facebook I've connected with people I knew and cared about that I haven't seen in 30 years. Dozens of them. I barely remembered person A and B, found them and became friends. Then they knew person C and D. E and F were close behind. Pretty soon I have 200 friends from places scattered all over the world.
Life sneaks up on you, and people stop having the same phone, email, or street address. You wake up one day wondering what happened to Bob, then slowly realize that you'll never see him again. It's a weird feeling.
Yes, if I were 20 and still had a cell phone with all my friends from 4 years ago, it'd be no big deal. But if I lost my FB data now? I'd never find these guys again.
Personal sidebar ahead: by the way, my wife and I are having a competition to see who can get the most friends. As long as you're not selling anything, and I promise not to sell you anything, send me an invite! Right now she has 600 friends and I have something like 250.
http://www.facebook.com/danielbmarkham